Field of the Invention
The present invention relates to a centrifugal fan and, more particularly, to a centrifugal fan having improved efficiency and noise.
Discussion of the Related Art
In general, a blower fan is used as a means for forcedly sending air using the rotary power of an impeller or rotor and is widely used in refrigerators, air-conditioners, and cleaners. In particular, the blower fan is divided into an axial flow fan, a sirocco fan, and a centrifugal fan depending on a method of sucking and discharging air or a shape thereof.
From among them, the centrifugal fan adopts a method of introducing air in the axial direction of the centrifugal fan and radially discharging the air through the side part of the centrifugal fan. The centrifugal fan does not require a duct because air is naturally introduced into the centrifugal fan and externally discharged, and is widely used in ceiling-attachment type air-conditioners, that is, relatively large products.
In such a centrifugal fan, blades are connected between a shroud into which air is introduced and a hub to which a rotary shaft is connected through welding or assembly. When the blade is rotated, a pressure difference is generated between the positive pressure surface and negative pressure surface of the blade. Accordingly, there are problems in that efficiency is reduced and noise is generated because a vortex is generated.